Both of them are fundraising to pay for exchange trips to the United States.

“Growing up with OI wasn’t an easy ride”, she said.

“I had begun to fracture before I was even born. I spent a lot of my childhood in hospital and I missed a lot of school.

“I physically wasn’t able to do the things the other kids my age did, and that definitely got me down at times.”

Lizzie hopes to travel to the Big Apple in October, for a two-week trip with Worthing College.

Anna plans to spend the first term of her second year at Bath Spa university studying at the State University of New York.

Both have set up Go Fund Me pages, in order to help fund the costly trips.

“It’s likely I may need to pay extra as I will need special insurance do to America’s costly health service, and if I fracture while I’m over there that’s going to be one big bill,” Lizzie said.

Anna, who has a milder form of OI than her sister, has suffered from a range of other health problems, including Crohn’s Disease.

She said: “What would be the chances that our dreams would come true, together?

“Since we both found out our applications had been successful, we have been trying to raise the funds for this opportunity but we do need help.”

Despite having had nearly 30 operations resulting in metal rods in both legs and metal pins in her spine, Lizzie has trained with the Paralympic Junior GB and South East Swimming team, and plays a number of other sports.

She has also taken part in charity events for Cancer Research and the area’s local hospices.

Visit the twins’ pages at www.gofundme.com/li9mwc and www.gofundme.com/klc45w

Lizzie has nearly reached her target but Anna still has several hundred pounds to raise.